Rear bumper for an automobile



FIG. 1 is a perspective view of the top, front and right side of a rear bumper for an automobile showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right side elevational view thereof; and,

FIG. 6 is a left side elevational view thereof.

The elements shown in broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a rear bumper for an automobile, as shown and described. 